A large collection of clonal rat cell lines of nerve, glial, smooth muscle, heart muscle, and skeletal muscle origin have been and will continue to be isolated in our laboratory. Many cell lines have been characterized biochemically and electrophysiologically, and along with cell lines isolated in other laboratories, will be used to study the differentiation, physiology, and interactions of nerve, muscle and glia. Emphasis will be placed upon the differentiation and adhesive interactions of mesodermally derived cells and the mode of action of nerve growth factor. The study of mesoderm development will be extended to the in vivo situation. Since secreted material plays a role and "trophic" and adhesive interactions between cells during morhogenesis the secreted proteins and glycosaminoglycans of nerve, glial, and muscle cell lines will be examined in detail. The role of extracellular substrate attached material in cell-substratum adhesion will also be examined. Quantitative two dimensional acrylamide gel methods for assaying protein synthesis will be used to examine secreted proteins as well as to follow protein synthesis during nerve and muscle differentiation and interaction.